In power tools and related devices, the motor housing comprises a field case, which may be made from a dielectric or insulating material (such as a suitable plastic which may be injection molded for economy of manufacture). The field case may include an integral web portion having a rear bearing boss and further having a plurality of circumferentially-spaced bridge members joining the rear bearing boss to the generally-cylindrical main portion of the field case. The universal motor includes an armature and a field. The field is inserted within the field case and is secured in it. The armature is inserted within the field and has a shaft journaled in a bearing in the rear bearing boss. A commutator is carried on the armature shaft, and spring-loaded brushes are slidably received in respective brush holders mounted on the field case for engagement with the commutator. With this arrangement the motor wire-up must often be conducted by hand.
Also, the prior art has resorted to various forms of manually-manipulatable reversing members. For example the reversing member may rotate a brush carrier pivotally mounted in the tool housing. Access to the reversing member is through an aperture in the tool housing.
While generally practical for the purposes intended, these structures (with or without the separate reversing mechanisms) are not readily adaptable to a wide range of power tools, appliances and other motor-driven devices for standardization of manufacture and assembly. Moreover, the electrical connection of the motors within the final product involves various wires and connections which further delay the overall assembly time, and inhibits realization of many benefits associated with automation of the assembly processes. This is especially important during the assembly of a compact power tool having relatively high motor performance and further having an overall "double insulated" design.